On Wed, Jul 15, 2020 at 02:18:39PM -0600, Mathieu Poirier wrote: > On Tue, Jul 07, 2020 at 12:07:49PM -0700, Siddharth Gupta wrote: > > Add the character device interface into remoteproc framework. > > This interface can be used in order to boot/shutdown remote > > subsystems and provides a basic ioctl based interface to implement > > supplementary functionality. An ioctl call is implemented to enable > > the shutdown on release feature which will allow remote processors to > > be shutdown when the controlling userpsace application crashes or hangs. > > > > Signed-off-by: Rishabh Bhatnagar <rishabhb@xxxxxxxxxxxxxx> > > Signed-off-by: Siddharth Gupta <sidgup@xxxxxxxxxxxxxx> > > --- > > Documentation/userspace-api/ioctl/ioctl-number.rst | 1 + > > drivers/remoteproc/Kconfig | 9 ++ > > drivers/remoteproc/Makefile | 1 + > > drivers/remoteproc/remoteproc_cdev.c | 146 +++++++++++++++++++++ > > drivers/remoteproc/remoteproc_internal.h | 28 ++++ > > include/linux/remoteproc.h | 5 + > > include/uapi/linux/remoteproc_cdev.h | 37 ++++++ > > 7 files changed, 227 insertions(+) > > create mode 100644 drivers/remoteproc/remoteproc_cdev.c > > create mode 100644 include/uapi/linux/remoteproc_cdev.h > > > > diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst > > index 59472cd..2a19883 100644 > > --- a/Documentation/userspace-api/ioctl/ioctl-number.rst > > +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst > > @@ -339,6 +339,7 @@ Code Seq# Include File Comments > > 0xB4 00-0F linux/gpio.h <mailto:linux-gpio@xxxxxxxxxxxxxxx> > > 0xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@xxxxxxxxxxxxxxx> > > 0xB6 all linux/fpga-dfl.h > > +0xB7 all uapi/linux/remoteproc_cdev.h <mailto:linux-remoteproc@xxxxxxxxxxxxxxx> > > 0xC0 00-0F linux/usb/iowarrior.h > > 0xCA 00-0F uapi/misc/cxl.h > > 0xCA 10-2F uapi/misc/ocxl.h > > diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig > > index c4d1731..652060f 100644 > > --- a/drivers/remoteproc/Kconfig > > +++ b/drivers/remoteproc/Kconfig > > @@ -14,6 +14,15 @@ config REMOTEPROC > > > > if REMOTEPROC > > > > +config REMOTEPROC_CDEV > > + bool "Remoteproc character device interface" > > + help > > + Say y here to have a character device interface for the remoteproc > > + framework. Userspace can boot/shutdown remote processors through > > + this interface. > > + > > + It's safe to say N if you don't want to use this interface. > > + > > config IMX_REMOTEPROC > > tristate "IMX6/7 remoteproc support" > > depends on ARCH_MXC > > diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile > > index e8b886e..311ae3f 100644 > > --- a/drivers/remoteproc/Makefile > > +++ b/drivers/remoteproc/Makefile > > @@ -9,6 +9,7 @@ remoteproc-y += remoteproc_debugfs.o > > remoteproc-y += remoteproc_sysfs.o > > remoteproc-y += remoteproc_virtio.o > > remoteproc-y += remoteproc_elf_loader.o > > +obj-$(CONFIG_REMOTEPROC_CDEV) += remoteproc_cdev.o > > obj-$(CONFIG_IMX_REMOTEPROC) += imx_rproc.o > > obj-$(CONFIG_INGENIC_VPU_RPROC) += ingenic_rproc.o > > obj-$(CONFIG_MTK_SCP) += mtk_scp.o mtk_scp_ipi.o > > diff --git a/drivers/remoteproc/remoteproc_cdev.c b/drivers/remoteproc/remoteproc_cdev.c > > new file mode 100644 > > index 0000000..8a0eb47 > > --- /dev/null > > +++ b/drivers/remoteproc/remoteproc_cdev.c > > @@ -0,0 +1,146 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > +/* > > + * Character device interface driver for Remoteproc framework. > > + * > > + * Copyright (c) 2020, The Linux Foundation. All rights reserved. > > + */ > > + > > +#include <linux/cdev.h> > > +#include <linux/fs.h> > > +#include <linux/module.h> > > +#include <linux/mutex.h> > > +#include <linux/compat.h> > > +#include <linux/remoteproc.h> > > +#include <linux/uaccess.h> > > +#include <uapi/linux/remoteproc_cdev.h> > > Alphabetical order please. > > > + > > +#include "remoteproc_internal.h" > > + > > +#define NUM_RPROC_DEVICES 64 > > +static dev_t rproc_major; > > + > > +static ssize_t rproc_cdev_write(struct file *filp, const char __user *buf, size_t len, loff_t *pos) > > +{ > > + struct rproc *rproc = container_of(filp->f_inode->i_cdev, struct rproc, char_dev); > > + int ret = 0; > > + char cmd[10]; > > + > > + if (!len || len > sizeof(cmd)) > > + return -EINVAL; > > + > > + ret = copy_from_user(cmd, buf, sizeof(cmd)); > > + if (ret) > > + return -EFAULT; > > + > > + if (sysfs_streq(cmd, "start")) { > > + if (rproc->state == RPROC_RUNNING) > > + return -EBUSY; > > + > > + ret = rproc_boot(rproc); > > + if (ret) > > + dev_err(&rproc->dev, "Boot failed:%d\n", ret); > > + } else if (sysfs_streq(cmd, "stop")) { > > + if (rproc->state != RPROC_RUNNING) > > + return -EINVAL; > > + > > + rproc_shutdown(rproc); > > + } else { > > + dev_err(&rproc->dev, "Unrecognized option\n"); > > + ret = -EINVAL; > > + } > > + > > + return ret ? ret : len; > > +} > > + > > +static long rproc_device_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) > > +{ > > + struct rproc *rproc = container_of(filp->f_inode->i_cdev, struct rproc, char_dev); > > + void __user *argp = compat_ptr(arg); > > + int ret; > > + int32_t param; > > + > > + switch (ioctl) { > > + case RPROC_SET_SHUTDOWN_ON_RELEASE: > > + ret = copy_from_user(¶m, argp, sizeof(int32_t)); > > + if (ret) { > > + dev_err(&rproc->dev, "Data copy from userspace failed\n"); > > + return -EFAULT; > > + } > > + mutex_lock(&rproc->lock); > > + rproc->cdev_put_on_release = param ? true : false; > > + mutex_unlock(&rproc->lock); > > + break; > > + case RPROC_GET_SHUTDOWN_ON_RELEASE: > > + mutex_lock(&rproc->lock); > > + ret = copy_to_user(argp, &rproc->cdev_put_on_release, sizeof(bool)); > > + mutex_unlock(&rproc->lock); > > + if (ret) { > > + dev_err(&rproc->dev, "Data copy to userspace failed\n"); > > + return -EFAULT; > > + } > > + break; > > + default: > > + dev_err(&rproc->dev, "Unsupported ioctl\n"); > > + return -EINVAL; > > + } > > + > > + return 0; > > +} > > + > > +static int rproc_cdev_release(struct inode *inode, struct file *filp) > > +{ > > + struct rproc *rproc = container_of(inode->i_cdev, struct rproc, char_dev); > > + bool release; > > + > > + mutex_lock(&rproc->lock); > > + release = rproc->cdev_put_on_release; > > + mutex_unlock(&rproc->lock); > > + > > + if (release && rproc->state == RPROC_RUNNING) > > I think the state of the processor should also be acquired when the lock is > held. There is still a chance ->state can change between the time the lock is > released and rproc_shutdown() is called but that's a known problem for which > patches have been sent out. > > > + rproc_shutdown(rproc); > > + > > + return 0; > > +} > > + > > +static const struct file_operations rproc_fops = { > > + .write = rproc_cdev_write, > > + .compat_ioctl = rproc_device_ioctl, > > + .release = rproc_cdev_release, > > +}; > > + > > +int rproc_char_device_add(struct rproc *rproc) > > +{ > > + int ret; > > + dev_t cdevt; > > + > > + cdev_init(&rproc->char_dev, &rproc_fops); > > + rproc->char_dev.owner = THIS_MODULE; > > + > > + cdevt = MKDEV(rproc_major, rproc->index); > > + ret = cdev_add(&rproc->char_dev, cdevt, 1); Trying this patchset on my side gave me the following splat[1]. After finding the root case I can't understand how you haven't see it on your side when you tested the feature. [1]. https://pastebin.com/aYTUUCdQ > > + if (ret < 0) > > + goto out; > > + > > + rproc->dev.devt = cdevt; > > +out: > > + return ret; > > +} > > + > > +void rproc_char_device_remove(struct rproc *rproc) > > +{ > > + __unregister_chrdev(rproc_major, rproc->index, 1, "remoteproc"); > > +} > > + > > +void __init rproc_init_cdev(void) > > +{ > > + int ret; > > + > > + ret = alloc_chrdev_region(&rproc_major, 0, NUM_RPROC_DEVICES, "remoteproc"); > > + if (ret < 0) > > + pr_err("Failed to alloc rproc_cdev region, err %d\n", ret); > > +} > > + > > +void __exit rproc_exit_cdev(void) > > +{ > > + unregister_chrdev_region(MKDEV(rproc_major, 0), NUM_RPROC_DEVICES); > > Please go back to the comment I made on this during my last review and respin. After digging in the code while debugging the above problem, I don't see how unregistering the chrdev region the way it is done here would have worked. > > > +} > > diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h > > index 4ba7cb5..f091ddc 100644 > > --- a/drivers/remoteproc/remoteproc_internal.h > > +++ b/drivers/remoteproc/remoteproc_internal.h > > @@ -47,6 +47,34 @@ extern struct class rproc_class; > > int rproc_init_sysfs(void); > > void rproc_exit_sysfs(void); > > > > +#ifdef CONFIG_REMOTEPROC_CDEV > > +void rproc_init_cdev(void); > > +void rproc_exit_cdev(void); > > +int rproc_char_device_add(struct rproc *rproc); > > +void rproc_char_device_remove(struct rproc *rproc); > > +#else > > +static inline void rproc_init_cdev(void) > > +{ > > +} > > + > > +static inline void rproc_exit_cdev(void) > > +{ > > +} > > + > > +/* > > + * The character device interface is an optional feature, if it is not enabled > > + * the function should not return an error. > > + */ > > +static inline int rproc_char_device_add(struct rproc *rproc) > > +{ > > + return 0; > > +} > > + > > +static inline void rproc_char_device_remove(struct rproc *rproc) > > +{ > > +} > > +#endif > > + > > void rproc_free_vring(struct rproc_vring *rvring); > > int rproc_alloc_vring(struct rproc_vdev *rvdev, int i); > > > > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h > > index e7b7bab..669cbfb 100644 > > --- a/include/linux/remoteproc.h > > +++ b/include/linux/remoteproc.h > > @@ -40,6 +40,7 @@ > > #include <linux/virtio.h> > > #include <linux/completion.h> > > #include <linux/idr.h> > > +#include <linux/cdev.h> > > Move this above completion.h > > With all of the above modifications: > > Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> I'm taking that back - this patch needs some fixing... > > > #include <linux/of.h> > > > > /** > > @@ -488,6 +489,8 @@ struct rproc_dump_segment { > > * @auto_boot: flag to indicate if remote processor should be auto-started > > * @dump_segments: list of segments in the firmware > > * @nb_vdev: number of vdev currently handled by rproc > > + * @char_dev: character device of the rproc > > + * @cdev_put_on_release: flag to indicate if remoteproc should be shutdown on @char_dev release > > */ > > struct rproc { > > struct list_head node; > > @@ -523,6 +526,8 @@ struct rproc { > > int nb_vdev; > > u8 elf_class; > > u16 elf_machine; > > + struct cdev char_dev; > > + bool cdev_put_on_release; > > }; > > > > /** > > diff --git a/include/uapi/linux/remoteproc_cdev.h b/include/uapi/linux/remoteproc_cdev.h > > new file mode 100644 > > index 0000000..c43768e > > --- /dev/null > > +++ b/include/uapi/linux/remoteproc_cdev.h > > @@ -0,0 +1,37 @@ > > +/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */ > > +/* > > + * IOCTLs for Remoteproc's character device interface. > > + * > > + * Copyright (c) 2020, The Linux Foundation. All rights reserved. > > + */ > > + > > +#ifndef _UAPI_REMOTEPROC_CDEV_H_ > > +#define _UAPI_REMOTEPROC_CDEV_H_ > > + > > +#include <linux/ioctl.h> > > +#include <linux/types.h> > > + > > +#define RPROC_MAGIC 0xB7 > > + > > +/* > > + * The RPROC_SET_SHUTDOWN_ON_RELEASE ioctl allows to enable/disable the shutdown of a remote > > + * processor automatically when the controlling userpsace closes the char device interface. > > + * > > + * input parameter: integer > > + * 0 : disable automatic shutdown > > + * other : enable automatic shutdown > > + */ > > +#define RPROC_SET_SHUTDOWN_ON_RELEASE _IOW(RPROC_MAGIC, 1, __s32) > > + > > +/* > > + * The RPROC_GET_SHUTDOWN_ON_RELEASE ioctl gets information about whether the automatic shutdown of > > + * a remote processor is enabled or disabled when the controlling userspace closes the char device > > + * interface. > > + * > > + * output parameter: integer > > + * 0 : automatic shutdown disable > > + * other : automatic shutdown enable > > + */ > > +#define RPROC_GET_SHUTDOWN_ON_RELEASE _IOR(RPROC_MAGIC, 2, __s32) > > + > > +#endif > > -- > > Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > > a Linux Foundation Collaborative Project > >
